Method and arrangement for coding transform coefficients in picture and/or video coders and decoders and a corresponding computer program and a corresponding computer-readable storage medium

ABSTRACT

A method and an arrangement for coding transform coefficients in picture and/or video coders and decoders and a corresponding computer program and a corresponding computer-readable storage medium are provided, which can particularly be employed as a novel efficient method for binary-arithmetic coding transform coefficients in the field of video coding. For this, it is suggested that, for blocks of (video) pictures containing significant transform coefficients, coding of the transform coefficients takes place in such a way that, for each block in a scan process, the positions of significant transform coefficients in the block and subsequently, in a reverse scan order—starting from the last significant transform coefficient within the block—the values (levels) of the significant transform coefficients are determined and coded.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional application of application Ser. No. 10/727,802,filed Dec. 4, 2003; which was a continuing application, under 35 U.S.C.§120, of International application PCT/EP03/04656, filed May 2, 2003;the application also claims the priority, under 35 U.S.C. §119, ofGerman patent application No. 102 20 961.8, filed May 2, 2002; the priorapplications are herewith incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention describes a method and an arrangement for codingtransform coefficients in picture and/or video coders and decoders and acorresponding computer program and a corresponding computer-readablestorage medium, which can particularly be employed as a novel efficientmethod for binary-arithmetic coding transform coefficients in the fieldof video coding (CABAC in H.264/AVC cf. [1]).

In present hybrid block-based standards for video coding, such as, forexample, MPEG-2 [2], H.263 [3] and MPEG-4 [4], the blocks of quantizedtransform coefficients (levels) are mapped by a defined scan process toa vector which is coded to code words having a variable length by usinga run-length coding and subsequent mapping.

In MPEG-2 [2], the code words having a variable length are associated totwo-dimensional events (RUN, LEVEL), wherein LEVEL represents thequantized value of a (significant) transform coefficient not quantizedto zero; the run-length RUN indicates the number of subsequent(non-significant) transform coefficients quantized to zero, which, inthe vector of transform coefficients, are immediately in front of thepresent significant transform coefficients. In addition, code wordshaving a variable length are defined for the two special events EOB andESCAPE. While the EOB event indicates that there are no furthersignificant transform coefficients in the block, the ESCAPE eventsignals that the existing event (RUN, LEVEL) cannot be represented bythe defined alphabet of code words having a variable length. In thiscase, the symbols RUN and LEVEL are coded by code words of a fixedlength.

In the newer coding standards H.263 (3] and MPEG-4 [4), the associationof code words having a variable length takes place on the basis ofthree-dimensional events (LAST, RUN, LEVEL), wherein the binary symbolLAST indicates whether the present significant transform coefficient isthe last significant coefficient within the block or whether furthersignificant transform coefficients follow. By using thesethree-dimensional events, no additional EOB event is required; an ESCAPEevent is used in analogy to MPEG-2, wherein the binary symbol LAST iscoded additionally to RUN and LEVEL.

The coding of the transform coefficients realized in MPEG-2, H.263 andMPEG-4 has the following disadvantages:

-   -   To each coding event only a code word having an integer length        can be associated, an efficient coding of events with        probabilities larger than 0.5 cannot take place.    -   The usage of a fixed table for mapping the coding events to the        code word having a variable length for all the transform        coefficients within a block does not consider symbol statistics        depending on position or frequency.    -   Adaptation to the actually existing symbol statistics is not        possible.    -   No usage is made of inter-symbol redundancies present.

Annex E of the H.263 standard specifies an optional non-adaptivearithmetic coding in which different predetermined model probabilitydistributions are used,

-   -   one each for the first, second and third event (LAST, RUN,        LEVEL)/ESCAPE    -   another one for all the following events (LAST, RUN,        LEVEL)/ESCAPE of a block of transform coefficients,    -   as well as one each for the symbols LAST, RUN and LEVEL, which        are coded after an ESCAPE event.

For the following reasons no appreciable increase of the codingefficiency is, however, possible by this optional arithmetic coding.

-   -   The advantage of arithmetic coding that a code word having a        non-integer length can be associated to a coding event hardly        has any effect on the coding efficiency by using combined events        of the form (LAST, RUN, LEVEL).    -   The advantage of using different probability distributions is        eliminated by the fact that adaptation to the actually present        symbol statistics is not possible.

One of the first published methods for coding transform coefficients byan adaptive binary arithmetic coding in a hybrid video coder ensuringthe adaptation of probabilities to the symbol statistics present hasbeen presented in [5].

In H.264/AVC [1], a context-adaptive method on the basis of code wordshaving a variable length for coding transform coefficients is specifiedas the standard method for entropy coding. Here, the coding of a blockof transform coefficients is determined by the followingcharacteristics:

-   -   Both the number of the significant coefficients within a block        and the number of subsequent coefficients quantized to one at        the end of the vector of transform coefficients are determined        by a symbol COEFF_TOKEN. Depending on the block type and the        symbols COEFF_TOKEN already coded/decoded for neighboring        blocks, one of five defined code word tables is chosen for        coding.    -   While for the transform coefficients quantized to one at the end        of the coefficient vector only a single bit is transferred for        specifying the sign, the coding of the values (levels) of the        remaining significant transform coefficients takes place in a        reverse scan order by means of a combined prefix suffix code        word.    -   If the number of significant transform coefficients is smaller        then the number of transform coefficients for the corresponding        block, a symbol TOTAL_ZEROS will be coded, which indicates the        number of transform coefficients quantized to zero which, in the        coefficient vector, are in front of the last significant        coefficient. For this, 18 code word tables have been specified,        which are switched depending on the number of significant        coefficients and the block type.    -   The run-length of the (non-significant) coefficients quantized        to zero (RUN) in front of a significant coefficient is coded for        each significant transform coefficient in a reverse scan order        as long as the sum of RUNs already coded is smaller than        TOTAL_ZEROS. Depending on TOTAL_ZEROS and the RUNs already        coded/decoded, switching between seven code word tables takes        place.

Although this so-called CAVLC method (CAVLC: context-adaptive variablelength coding), by context based switching the code word tables, allowsa considerably more efficient coding of the transform coefficients thanthe methods specified in MPEG-2, H.263 and MPEG-4, it basically has thefollowing disadvantages:

-   -   Switching between different code word tables takes place        depending on symbols already coded/decoded, the code word        tables, however, cannot be adjusted to the actual symbol        statistics.    -   By using code words having a variable length, events having        symbol probabilities larger than 0.5 cannot be coded        efficiently. This limitation especially prevents coding symbols        having a smaller value range, by means of which a construction        of suitable contexts might be possible for switching between        different model probability distributions.

A possible solution for avoiding the disadvantages illustrated ofwell-known methods for coding transform coefficients in block-basedpicture and video coders is a combination of an adaptive arithmeticcoding and a suitable context generation for using the inter-symbolredundancies. Since the more complicated computing of the arithmeticcoding, compared to coding by means of code words having a variablelength, is a disadvantage, the possibility of an efficient hardware andsoftware implementation must be considered particularly.

SUMMARY OF THE INVENTION

Thus, it is the object of the present invention to provide a method andan arrangement for coding transform coefficients in picture and/or videocoders and decoders and a corresponding computer program and acorresponding computer-readable storage medium, which eliminate thedeficiencies mentioned above and, in particular, keep the amount ofcalculating required for coding small.

According to the invention, this object is achieved by thecharacteristics in claims 1, 10, 11 and 12. Practical embodiments of theinvention are contained in the subclaims.

It is a special advantage of the inventive method that, for blocks of(video) pictures containing significant transform coefficients, thecoding of transform coefficients takes place in such a way that, foreach block,

-   -   in a scan process, the positions of significant transform        coefficients in the block and subsequently,    -   in a reverse scan order—starting with the last significant        transform coefficients within the block—the values (levels) of        the significant transform coefficients are determined and coded.

One preferred embodiment of the inventive method is characterized byeach significant transform coefficient of the block other than the lasttransform coefficient of the block being characterized by a one-bitsymbol.

It is also of advantage if the sign for each significant transformcoefficient is indicated by a one-bit symbol (SIGN) and the magnitude isindicated by a binary coded symbol (ABS).

In one preferred embodiment of the inventive method, blocks containingsignificant transform coefficients are characterized by a one-bit symbolCBP4 in connection with other syntax elements, such as, for example, CBPor macro block mode.

It is a special advantage of the method that, by transferring a one-bitsymbol SIG for each coefficient of a block and of a one-bit symbol LASTfor each significant coefficient of a block, a significance mapping iscoded, wherein the transfer takes place in the scan order, SIG servesfor identifying significant coefficients and LAST indicates whetherthere are further significant transform coefficients in the block.

In another preferred embodiment of the inventive method, modeling forthe one-bit symbol CBP4, for coding the significance mapping and/or forcoding the coefficient magnitudes takes place in a context-dependentway. Thus, block types of transform coefficients having comparablestatistics are summarized to block categories.

It is also of advantage that, in a special embodiment of the inventivemethod, no significance information (SIG, LAST) is transferred for thelast scan position of a block.

In a preferred embodiment of the inventive method, the magnitude (ABS)is indicated by a symbol in unary binarization or by a symbol having aprefix part and a suffix part, wherein the prefix part consists of onesand the suffix part is coded in a 0^(th) order exp-golomb code.

An arrangement for coding transform coefficients in picture and/or videocoders and decoders is, preferably, formed such that it includes atleast one processor and/or chip formed such that a coding of transformcoefficients can be performed, wherein for blocks of (video) picturescontaining significant transform coefficients, the coding of transformcoefficients takes place in such a way that, for each block,

-   -   in a scan process, the positions of significant transform        coefficients in the block and subsequently,    -   in a reverse scan order—starting with the last significant        transform coefficients within the block—the values (levels) of        the significant transform coefficients are determined and coded.

A computer program for coding transform coefficients in picture and/orvideo coders and decoders is characterized by enabling a computer, afterhaving been loaded into the memory of the computer, to perform a codingof transform coefficients, wherein for blocks of (video) picturescontaining significant transform coefficients, the coding of transformcoefficients takes place in such a way that, for each block,

-   -   in a scan process, the positions of significant transform        coefficients in the block and subsequently,    -   in a reverse scan order—starting with the last significant        transform coefficients within the block—the values (levels) of        the significant transform coefficients are determined and coded.

In order to perform coding of transform coefficients, acomputer-readable storage medium is preferably employed, on which aprogram is stored, enabling a computer, after having been loaded intothe memory of the computer, to perform a method for coding transformcoefficients in picture and/or video coders and decoders, wherein forblocks of (video) pictures containing significant transformcoefficients, the coding of transform coefficients takes place in such away that, for each block,

-   -   in a scan process, the positions of significant transform        coefficients in the block and subsequently,    -   in a reverse scan order—starting with the last significant        transform coefficients within the block—the values (levels) of        the significant transform coefficients are determined and coded.

The novel method for coding transform coefficients is especiallycharacterized by the following characteristics:

-   -   A two-dimensional block of transform coefficients is mapped to a        one-dimensional vector by a scan process.    -   The syntax elements of the EOB symbol, the LAST symbol or the        coefficient counter (number of significant coefficients) as well        as RUN (number of non-significant coefficients in the scan        order) used in well-known methods are replaced by a one-bit        symbol CBP4 and a significance mapping.    -   The levels (magnitudes of the significant coefficients) are        coded in a reverse scan order.    -   Context modeling takes place in a novel manner.

Other features which are considered as characteristic for the inventionare set forth in the appended claims.

Although the invention is illustrated and described herein as embodiedin method and arrangement for coding transform coefficients in pictureand/or video coders and decoders and a corresponding computer programand a corresponding computer-readable storage medium, it is neverthelessnot intended to be limited to the details shown, since variousmodifications and structural changes may be made therein withoutdeparting from the spirit of the invention and within the scope andrange of equivalents of the claims.

The construction and method of operation of the invention, however,together with additional objects and advantages thereof will be bestunderstood from the following description of specific embodiments whenread in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of the basic principle of coding transformcoefficients according to the inventive coding method,

FIG. 2 shows two examples for coding the significance mapping (theyellow marked symbols are not transferred),

FIG. 3 shows binarization for the transform coefficients (ABS),

FIG. 4 shows block types and their classification for the H.264/AVCstandard,

FIG. 5 shows context modeling for the one-bit symbol CBP4, and

FIG. 6 shows examples of the context modeling for coding the magnitudesof the significant transform coefficients.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates the novel coding method. For each block of transformcoefficients, a one-bit symbol CBP4 is transferred at first, unlesshigher order syntax elements (CBP or macro block mode) already indicatethat the block considered does not contain any significant transformcoefficients. The CBP4 symbol will be zero if there are no significantcoefficients in the block. If it is one, a significance mappingspecifying the position (in scan order) of the significant transformcoefficients will be coded. Subsequently, the magnitude and the signs ofthe significant coefficients are transferred in a reverse scan order. Adetailed description of the coding process will be given below in 1.Afterwards, context modeling for the binary arithmetic coding will bedescribed in 2.

1. Description of the Coding of the Transform Coefficients

1.1 Scanning Transform Coefficients

The transform coefficients of each block are mapped to a vector by meansof a scan process (such as, for example, a zig zag scan).

1.2 CBP4 Symbol

CBP4 is a one-bit symbol indicating whether there are significanttransform coefficients (transform coefficients unequal to zero) in ablock. If the CBP4 symbol is zero, no further information for thecorresponding block will be transferred.

1.3 Significance Mapping

If the CBP4 symbol indicates that the corresponding block containssignificant coefficients, a significance mapping will be coded. Thistakes place by transferring a one-bit symbol (SIG) for each coefficientin the scan order. If a corresponding significance symbol is one(significant coefficient), another one-bit symbol (LAST) will betransferred. This symbol indicates whether the present significantcoefficient is the last significant coefficient within a block orwhether further significant coefficients follow. FIG. 2 shows twoexamples of the method described for coding the significance mapping.Significance information (SIG, LAST) will never be transferred for thelast scan position of a block. If the transfer of the significancemapping has not already been terminated by a LAST symbol of one, it isobvious that the coefficient at the last scan position is significant(see yellow marked position in FIG. 2).

1.4 Level Information

The positions of the significant transform coefficients within a blockare clearly specified by the significance mapping. The coding of theprecise values of the coefficients (levels) takes place by two codingsymbols: ABS (magnitude of the coefficients) and SIGN (sign of thecoefficients). While SIGN represents a one-bit symbol, binarizationaccording to FIG. 3 is used for coding the magnitudes of thecoefficients (ABS). For coefficient magnitudes in the interval (1; 14),this binarization corresponds to a unary binarization. The binarizationfor coefficient magnitudes larger than 14 consists of a prefix partconsisting of 14 ones and a suffix part representing a 0^(th) orderexp-golomb code for the symbol (ABS-15). Binarization does not include arepresentation for coefficient magnitudes (ABS) equaling 0, sincesignificant coefficients (coefficients unequal to zero) will always havea magnitude (ABS) larger than or equal to one.

The binarization formed of a prefix part and a suffix part consisting ofa 0^(th) order exp-golomb code for coefficient magnitudes larger than 14has the advantage that a special non-adaptive context with symbolprobabilities 0.5 can be used without sacrificing in coding efficiencyfor all the binary decisions of the suffix part, whereby the amount ofcalculating for encoding and decoding can be reduced.

The levels are coded in a reverse scan order—beginning with the lastsignificant coefficient within the block; this enables forming suitablecontexts for the binary arithmetic coding.

2. Context Modeling

In general, different types of transform coefficient blocks aredifferentiated when considering a picture and/or video coding system.Thus, there are, for example, twelve types of transform coefficientblocks, having different statistics (the left column of table in FIG. 4)in the present Final Draft International Standard [1] of the H.264/AVCstandard. For most picture sequences and coding conditions, some of thestatistics are, however, very similar. In order to keep the number ofcontexts used small and thus to ensure a quick adaptation to thestatistic of the picture sequence to be coded, the block types, in theH.264/AVC standard, can, for example, be classified into five categories(see right column of table in FIG. 4). Similar classifications arepossible for other picture and/or video coding systems. For each ofthe—in the case of the H.264/AVC standard—five categories, an individualquantity of contexts is used for the symbols CBP4, SIG, LAST and ABS.

2.1 Context Modeling for the CBP4 Symbol

For coding the one-bit symbol CBP4, four different contexts are used foreach individual category of transform blocks (see FIG. 4). The contextnumber for block C to be coded is determined byctx_number_cbp4 (C)=CBP4 (A)+2×CBP4 (B)wherein those neighboring blocks (left and top) of block C considered tobe associated to the same block type are designated by A and B.Regarding the H.264/AVC standard, the following 6 block types aredifferentiated for this conditioning: Luma-DC, Luma-AC, Chroma-U-DC,Chroma-U-AC, Chroma-V-DC and Chroma-V-AC. If the concerning block X (Aor B) of transform coefficients does not exist in a neighboring macroblock (this is, for example, the case if the present block is coded inthe INTRA16×16 mode, but the neighboring block has been transferred inan INTER mode), CBP4 (X) is set to zero for the neighboring block X. Ifa neighboring block X (A or B) is outside the picture area or belongs toanother slice, the corresponding value CBP4 (X) is replaced by a defaultvalue. A default value of one is used for INTRA-coded blocks and adefault value of zero is used for INTER-coded blocks.2.2 Context Modeling for Coding the Significance Mapping

For coding the significance mapping, max_koeff−1 different contexts areeach used per block category (see FIG. 4) for coding the symbols SIG andLAST. max_koeff thus designates the number of transform coefficients forthe corresponding block category (for H.264/AVC, see FIG. 4).

The context number is always indicated by the corresponding scanposition of the coefficient considered. The context numbers of acoefficient koeff[i], which has been scanned as an i-th coefficient,thus result in:ctx_number_sig(koeff[i])=ctx_number_last{koeff[i])=i.2*max_koeff−2 contexts are used for each category of block types forcoding the significance mapping.2.3 Context Modeling for Coding Coefficient Magnitudes

The binarization illustrated in FIG. 3 is used for coding the magnitudesof the significant transform coefficients. Two different contextquantities are used per block category, namely one for coding the firstbinary decision bin=1 (marked orange in FIG. 3) and another one forcoding the is binary decisions bin=2 . . . 14 (marked green in FIG. 3)of the binarization. The context numbers are thus associated as follows:ctx_number_abs_(—)1bin=(koeff with ABS>1 coded? 4: max(3, number ofcoded coefficients with ABS=1)),ctx_number_abs_rbins=max(4, number of coded coefficients with ABS>1)).

The magnitudes of the transform coefficients are transferred in areverse scan order. The context for the first binary decision isdetermined by the number of coefficients already transferred (in reversescan order) having a magnitude of ABS=1. If more than three coefficientswith a magnitude ABS=1 have already been transferred, context number 3will always be chosen. As soon as a coefficient having a magnitude ABS>1has been transferred, context 4 will be used for all the remainingsignificant coefficients within the block.

All binary decisions with bin=2 . . . 14 are coded using one and thesame context. Thus, the context number is determined by the number ofcoefficients already coded (in a reverse scan order) having a magnitudeof ABS>1, wherein the maximum context number is limited to 4. Forillustration, two examples for the context selection, when coding themagnitudes ABS of the significant transform coefficients, areillustrated in FIG. 6. For coding the binary decision bin>14 for thecoefficient magnitudes and for the signs SIGN, an individualnon-adaptive context with the symbol probabilities P₀=P₁=0.5 is used.

The invention, in its embodiment, is not limited to the preferredembodiments indicated hereinbefore. A number of variations making use ofthe inventive arrangement and of the inventive method, even if thedesign is completely different, are feasible.

1. A method for arithmetically coding magnitudes of coefficients,comprising the following steps: providing transform coefficientsrepresenting a picture or a video; binarizing magnitudes of thetransform coefficients into a binarization such that for magnitudessmaller than or equal to a predetermined value the binarizationcorresponds to a unary binarization and such that for magnitudes largerthan the predetermined value the binarization is composed of a prefixpart consisting of a number of ones corresponding to the predeterminedvalue and of a suffix part representing an 0^(th) order exp-golomb partfor the magnitude of the respective transform coefficient minus thepredetermined value incremented by one; binary-arithmetic coding binarydecisions of the suffix part using a non-adaptive context; andbinary-arithmetic coding at least one binary decision of thebinarization corresponding to a unary binarization or the prefix partusing a context with adaptation.
 2. The method according to claim 1,wherein the binary arithmetic coding of the binary decisions of thesuffix part using a non-adaptive context is performed using a symbolprobability of 0.5.
 3. The method according to claim 1, wherein thepredetermined value is
 14. 4. The method according to claim 1, whereinthe binarization is performed such that the magnitudes are indicated bya symbol (ABS) in unary binarization or by a symbol (ASS) having aprefix part and a suffix part, and such that the prefix part consists ofones and the suffix part is coded in a 0^(th) order exp-golomb code. 5.A method for arithmetically decoding magnitudes of transformcoefficients binarized such that for magnitudes smaller than or equal toa predetermined value the binarization corresponds to a unarybinarization and such that for magnitudes larger than the predeterminedvalue the binarization is composed of a prefix part consisting of anumber of ones corresponding to the predetermined value and of a suffixpart representing an 0^(th) order exp-golomb part for the magnitude ofthe respective transform coefficient minus the predetermined valueincremented by one, comprising the following steps: binary-arithmeticdecoding binary decisions of the suffix part using a non-adaptivecontext; and binary-arithmetic decoding at least one binary decision ofthe binarization corresponding to a unary binarization or the prefixpart using a context with adaptation; wherein the transform coefficientsrepresent a picture or a video.
 6. The method according to claim 5,wherein the binary arithmetic decoding of the binary decisions of thesuffix part using a non-adaptive context is performed using a symbolprobability of 0.5.
 7. The method according to claim 5, wherein thepredetermined value is
 14. 8. The method according to claim 5, whereinthe binarization is performed such that the magnitudes are indicated bya symbol (ABS) in unary binarization or by a symbol (ASS) having aprefix part and a suffix part, and such that the prefix part consists ofones and the suffix part is coded in a 0^(th) order exp-golomb code. 9.A device for arithmetically coding magnitudes of transform coefficients,comprising: means for binarizing the magnitudes of the transformcoefficients into a binarization such that for magnitudes smaller thanor equal to a predetermined value the binarization corresponds to aunary binarization and such that for magnitudes larger than thepredetermined value the binarization is composed of a prefix partconsisting of a number of ones corresponding to the predetermined valueand of a suffix part representing an 0^(th) order exp-golomb part forthe magnitude of the respective transform coefficient minus thepredetermined value incremented by one; means for binary-arithmeticcoding binary decisions of the suffix part using a non-adaptive context;and means for binary-arithmetic coding at least one binary decision ofthe binarization corresponding to a unary binarization or the prefixpart using a context with adaptation.
 10. The device according to claim9, wherein the transform coefficients represent a picture or a video.11. A device for arithmetically decoding magnitudes of transformcoefficients binarized such that for magnitudes smaller than or equal toa predetermined value the binarization corresponds to a unarybinarization and such that for magnitudes larger than the predeterminedvalue the binarization is composed of a prefix part consisting of anumber of ones corresponding to the predetermined value and of a suffixpart representing an 0^(th) order exp-golomb part for the magnitude ofthe respective transform coefficient minus the predetermined valueincremented by one, comprising: means for binary-arithmetic decodingbinary decisions of the suffix part using a non-adaptive context; andmeans for binary-arithmetic decoding at least one binary decision of thebinarization corresponding to a unary binarization or the prefix partusing a context with adaptation.
 12. The device according to claim 11,wherein the transform coefficients represent a picture or a video.
 13. Acomputer-readable storage medium having stored thereon a computerprogram for performing a method for arithmetically coding magnitudes ofcoefficients, the method comprising the following steps: providingtransform coefficients representing a picture or a video; binarizingmagnitudes of the transform coefficients into a binarization such thatfor magnitudes smaller than or equal to a predetermined value thebinarization corresponds to a unary binarization and such that formagnitudes larger than the predetermined value the binarization iscomposed of a prefix part consisting of a number of ones correspondingto the predetermined value and of a suffix part representing an 0^(th)order exp-golomb part for the magnitude of the respective transformcoefficient minus the predetermined value incremented by one;binary-arithmetic coding binary decisions of the suffix part using anon-adaptive context; and binary-arithmetic coding at least one binarydecision of the binarization corresponding to a unary binarization orthe prefix part using a context with adaptation.
 14. A computer-readablestorage medium having stored thereon a computer program for performing amethod for arithmetically decoding magnitudes of transform coefficientsbinarized such that for magnitudes smaller than or equal to apredetermined value the binarization corresponds to a unary binarizationand such that for magnitudes larger than the predetermined value thebinarization is composed of a prefix part consisting of a number of onescorresponding to the predetermined value and of a suffix partrepresenting an 0^(th) order exp-golomb part for the magnitude of therespective transform coefficient minus the predetermined valueincremented by one, comprising the following steps: binary-arithmeticdecoding binary decisions of the suffix part using a non-adaptivecontext; and binary-arithmetic decoding at least one binary decision ofthe binarization corresponding to a unary binarization or the prefixpart using a context with adaptation; wherein the transform coefficientsrepresent a picture or a video.